// 名字空间演示

#include <iostream>
#include <math.h>
using namespace std;

namespace MyOwn {
    int rand();
    int sqrt();
}

int MyOwn::rand() {
    return 42;
}

int MyOwn::sqrt() {
    return 52;
}

int main() {
    srand(123);

    int stdRand = rand();
    cout << "标准rand输出的数是: " << stdRand << "\n";

    int myRand = MyOwn::rand();
    cout << "自定义rand输出的数是: " << myRand << "\n";

    double realSqrt = sqrt(25.0);
    cout << "标准sqrt输出: " << realSqrt << "\n";

    int mySqrt = MyOwn::sqrt();
    cout << "自定义的sqrt输出: " << mySqrt << "\n";

    cout << "完毕\n";
}